(A) study on analysis methodology for dynamic characteristics of check valves in nuclear power plant using CFD

Abstract

The present study provides recommendations for choosing the appropriate dynamic mesh techniques of computational fluid dynamics(CFD) to describe the dynamic characteristics of a check valve in nuclear power plants. Four different methods were proposed to simulate the check valve closure using the dynamic mesh techniques of CFD, and strategies were also proposed to describe the full closure of the valve. The closing behavior of the 10-inch check valve installed in the nuclear power plant was measured. The actual closing of the check valve was analyzed by applying the four methodologies proposed in this study, and the analysis results were compared with the measurement. In addition, the analysis models were generated to simulate the check valve closure with a constant angular velocity for comparison between each method, and the pressure build-up in response to the valve’s closing behavior were evaluated. The results showed that the check valve’s dynamic behavior during the valve closure could be well described by the proposed methods, and there was no significant difference beween each method in terms of fluid velocity and pressure around the disc. The velocity profiles at the outlet of each method were similar until the valve was almost closed. However, even though the proposed methods described the check valve’s closing behavior well, the predictions of the inflow velocity for the immersed boundary method when the valve was fully closed were different from the other methods.